I also have some issues with subtitles on my Samsung tv.
I also mentioned it in LG Version : 5.44.3 broke subtitles as my LG tv also issues.
The issue is that my QN90A only shows some PGS subtitles.
An older movie’s PGS subtitles are shown, but a newly added blu-ray with two audio tracks (English and native) and with two subtitles tracks (native - forced and native) does not get shown unless I switch to “Always burn-in”, without “Always burn-in” sometimes right after a forced line would have been shown I might see a line of the selected subtitle track
Both my android phone and the Windows app shows the selected subtitles for both movies without issues